Effects of late summer fire on tallgrass prairie microclimate and community composition

Abstract

Headfires were ignited on 5 September 1985 under wildfire weather conditions (37°C air temperature, 36% RM and wind gusts to 40 km/h). One of the burned plots had not been grazed for the past 3 yr and had 1000 g/m2 fine fuel load; the other had been grazed moderately and had 450 g/m2 fine fuel. Fire intensity at the soil surface on the high fuel-load plot was 4 times that on the low fuel burn plot. The year following burning, vegetative parameters, including tiller density, basal area and production, indicated that rhizomatous tallgrasses revegetated both burned plots quickly. Bunchgrasses decreased in both basal area and production on the high fuel plot. Community composition and productivity differences persisted 1 yr after the fires and were mainly attributable to bunchgrass mortality and microhabitat improvement for ruderal species. Fire intensity is thus an important factor to consider when developing fire disturbance theory for tallgrass prairie. -from Authors